The chasis is 100% the same (engine, weight, towing capacity, etc). The difference is 'options' selected and used (Radio, Seats, etc).
The big difference is floorplan and materials (and equipment) being used by the manufacturers.
The Winnebago View/Itasca Navion wins if you care about leather seats for the cab and a second radio in the coach as well as aerodynamic (not as tall and better front profile). However everything comes at a price and I just could not justify the 20K+ price difference.
The Coachman Prism looks interesting but I guess it will be priced/positioned against the Winnebago and carry a very similar price. For that price I would have preferred the Mercedes Grill (like the Winnebago) and not the Freightliner grill.....
We considered the Four Winds as well but no dealer in the area is willing to stock them (must be due to the 2009 chasis which is still Dodge branded and lacks a few horsepower) but priced like a Winnebago.
For us the Solera provided the most room in the living quarters and price/value was the best compromise we found. I would have taken the Winnebago if the price would be more 'realistic' on those (part of the problem was dealer only has the full paint option which is zero value when you sit inside and lots of $$$).